Removal of High-Concentration Sulfate from Seawater by Ettringite Precipitation

Figure 4

Effects of different concentrations of Na⁺ ions on the sulfate concentration in treated NaCl solutions by the ettringite method. The initial sulfate concentration is 4,290 ppm, and the added chemical dosage of Al : Ca : S is at a molar ratio of 2 : 6 : 1. The RSD of sulfate concentration is less than 10%.